Demolition hammers are used on work sites to break up objects such as rocks, concrete, asphalt, frozen ground, or other hard objects. The hammers may be mounted to machines, such as backhoe loaders, skid steer loaders and excavators, or may be hand-held. The hammers may be powered by a hydraulic or pneumatic pressure source. In one example of an operation, a high pressure fluid drives a piston to strike a tool bit, which in turn, strikes rock, concrete, asphalt or other hard object to be broken up.
Lubrication systems are used to supply lubricant, such as grease, to bearing surfaces in the hammer to reduce friction between moving parts, such as between the tool bit and bushings that are used to align the tool bit. The lubrication system may be mounted to the hammer, i.e., mounted on the work tool. A lubricant supply is provided with the system. Operating the hammers without lubrication can result in significant damage to the hammer.
U.S. Pat. No. 7,694,748, to Oksman, describes a lubrication system for work tools, such as hammers and drills. The lubrication system is mounted on the tool itself in order to be closer to the points requiring lubrication. This patent describes work tools that generate impact pulses to break rocks and drill into rocks, in a manner similar to other construction machines.
The '748 patent provides lubricant and a lubrication system that is close to the points requiring lubrication on the work tool. However, the impact pulses that are used in the normal course of operating the machines also have an effect on the operation of the lubrication system. The constant vibration and the repetitive nature of the method of operation can adversely affect operation of the lubrication system. The vibrations reduce the life of the hoses used to provide hydraulic or pneumatic fluid to power the lubrication system. The vibrations can also loosen or weaken the connections with the fluid power lines and the lubricant lines, which could result in loss of lubrication to the work tool. In addition, the lubrication system, mounted on the tool itself, may be damaged if the tool is moved into and maneuvered within a confined space, such as a trench.